staging: comedi: dt9812: convert digital out subdevice to (*insn_bits)

Currently the (*insn_write) function for the digital output subdevice
only sets the state for a single channel. It's more efficent to use
the (*insn_bits) function and allow setting the state for all the
channels.

The comedi core can use the (*insn_bits) to emulate the (*insn_write)
if needed.

Also, use the subdevice 'state' variable to hold the current state
of the channels instead of 'do_shadow' in the private data.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/staging/comedi/drivers/dt9812.c b/drivers/staging/comedi/drivers/dt9812.c
index 4fd15162f4b60909c3f2177aa25d1d7562d03dd5..7f6d43a33de347ed5c2a1039c4b5602ea44d916e 100644 (file)
--- a/drivers/staging/comedi/drivers/dt9812.c
+++ b/drivers/staging/comedi/drivers/dt9812.c
@@ -265,7 +265,6 @@ struct dt9812_private {
        } cmd_wr, cmd_rd;
        u16 device;
        u16 ao_shadow[2];
-       u8 do_shadow;
 };
 
 static int dt9812_read_info(struct comedi_device *dev,
@@ -390,23 +389,11 @@ static int dt9812_digital_out(struct comedi_device *dev, u8 bits)
 
        down(&devpriv->sem);
        ret = dt9812_write_multiple_registers(dev, 1, reg, value);
-       devpriv->do_shadow = bits;
        up(&devpriv->sem);
 
        return ret;
 }
 
-static int dt9812_digital_out_shadow(struct comedi_device *dev, u8 *bits)
-{
-       struct dt9812_private *devpriv = dev->private;
-
-       down(&devpriv->sem);
-       *bits = devpriv->do_shadow;
-       up(&devpriv->sem);
-
-       return 0;
-}
-
 static void dt9812_configure_mux(struct comedi_device *dev,
                                 struct dt9812_rmw_byte *rmw, int channel)
 {
@@ -624,24 +611,24 @@ static int dt9812_di_insn_bits(struct comedi_device *dev,
        return insn->n;
 }
 
-static int dt9812_do_winsn(struct comedi_device *dev,
-                          struct comedi_subdevice *s, struct comedi_insn *insn,
-                          unsigned int *data)
+static int dt9812_do_insn_bits(struct comedi_device *dev,
+                              struct comedi_subdevice *s,
+                              struct comedi_insn *insn,
+                              unsigned int *data)
 {
-       unsigned int channel = CR_CHAN(insn->chanspec);
-       int n;
-       u8 bits = 0;
+       unsigned int mask = data[0];
+       unsigned int bits = data[1];
 
-       dt9812_digital_out_shadow(dev, &bits);
-       for (n = 0; n < insn->n; n++) {
-               u8 mask = 1 << channel;
+       if (mask) {
+               s->state &= ~mask;
+               s->state |= (bits & mask);
 
-               bits &= ~mask;
-               if (data[n])
-                       bits |= mask;
+               dt9812_digital_out(dev, s->state);
        }
-       dt9812_digital_out(dev, bits);
-       return n;
+
+       data[1] = s->state;
+
+       return insn->n;
 }
 
 static int dt9812_ai_rinsn(struct comedi_device *dev,
@@ -849,9 +836,7 @@ static int dt9812_auto_attach(struct comedi_device *dev,
        s->n_chan       = 8;
        s->maxdata      = 1;
        s->range_table  = &range_digital;
-       s->insn_write   = dt9812_do_winsn;
-
-       devpriv->do_shadow = 0;
+       s->insn_bits    = dt9812_do_insn_bits;
 
        /* Analog Input subdevice */
        s = &dev->subdevices[2];